


Harry Potter and the Misdirected Growth Charm

by odetojoie



Category: Harry Potter - J. K. Rowling
Genre: F/M, Hogwarts, Hogwarts Express
Language: English
Status: Completed
Published: 2017-04-12
Updated: 2017-04-12
Packaged: 2018-10-17 22:29:23
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,367
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10603587
Author URL: https://archiveofourown.org/users/odetojoie/pseuds/odetojoie
Summary: Harry, Ron, and Hermione learn why underage wizards shouldn't perform magic outside of Hogwarts the *hard* way.





	

Part 1: A Growing Problem

It had been pretty uneventful, as far as Hogwarts Express rides went. The sweets cart had come and gone, and Harry had treated his friends to a smorgasbord of sugary confections. After the initial sugar high, Harry felt himself beginning to get drowsy. Harry looked out the window of the car at the passing scenery and felt his eyelids begin to droop. 

As usual, Hermione was boasting about how she’d already memorized this upcoming year’s worth of books for their classes, and which spells she’d been dying to practice all summer (as Hogwarts students were forbidden to use magic outside of school grounds). In typical Hermione fashion, she began to recite all of the charms she had memorized; her current favorites, so far, were the Shrinking and Growth Spells (which, she informed Harry and Ron in a confidential stage-whisper, she had already used to fit additional textbooks into her luggage this year: “It was for school, so it doesn’t exactly count!"). 

Ron, who was thoroughly disinterested in any sort of learning at the moment (“Save the lecture for class, Hermione!") had begun to flip through a Quidditch magazine, and was only offering minimal affirmative grunts. Undeterred, Hermione opened one of her bags and proudly displayed the mass of meticulously-packed miniatures inside. 

“See this, Ron? I managed to shrink them all to the same exact size, so they all stacked neatly. And they lose weight proportionally to their size! Isn’t that fascinating?” 

“Riveting,” yawned Ron as he eyed the small mountain of candies and selected a Chocolate Frog. “How much farther to Hogwarts?"

Harry began drowsing off just as Hermione started to instruct Ron on the proper pronunciation of Shrinking and Growth Spells. (“You put the stress on the second syllable, en-GOR-gio, just like that, and do a small turn of your wrist to control the rate of growth.”)

Ron sniggered, wiggling his eyebrows. “I know something I’d like to grow with that spell.”

Hermione sniffed disapprovingly. “Ron, really.” Then her eyes alighted on an tattered duffel bag Ron had been struggling with earlier. “Here, I can help you fit that pack inside your other trunk.” 

Ron shrugged apathetically, but Hermione was already eagerly unsheathing her wand. “Reducio!” Within a moment, the duffel shrank to the size of a small pea. 

Ron choked in surprise on his Chocolate Frog. “Hey! I still need that to be visible, at least. I’m going to lose it if you make it any smaller."

Hermione grinned, a little embarrassed. “Sorry, I got a bit overexcited. I’m still perfecting the size-adjustments… it’s all in the wrist, you know.” 

Ron huffed. “Yeah, well, don’t go sacrificing my things while you’re still experimenting, you show-off.”

Hermione rolled her eyes. “It’s fine, Ron. Watch this.” Hermione picked up the shrunken duffel in her hand and pronounced, “Engorgio!” But just as she opened her mouth to enunciate and swished her wand, the enchanted train lurched forward unexpectedly at a bump in the tracks, and Hermione’s hand jolted accidentally. The wand ended up pointing directly at Harry’s exposed crotch at the precise moment she finished uttering the last syllable. Hermione and Ron stared in horror.

— — — 

From the haze of his dream, Harry stirred uncomfortably. He’d just been about to take Buckbeak out for a lap over the Forbidden Forest, when, to his shock and chagrin, the kneeling hippogriff laid it’s feathery head in his crotch and began to nudge him rather insistently. Though Harry was mortified, his body immediately began to react to the soft, insistent pressure. 

Hermione’s little embarrassed shriek roused him, and he realized gratefully that he was actually just dozing off on the Hogwarts Express. Then his gratitude faded into curiosity as he noticed his friends were covering their eyes. 

“Well, it worked,” Hermione squeaked uncomfortably, her ears taking on a pinkish tint.

Ron coughed, his face scarlet. “I see.. though I wish I hadn’t.”

Harry looked down, immediately wide awake. The effects of Hermione’s wayward charm had become immediately prominent. Harry was sporting an erection the size of which he had never seen before, not even in the dirty mags Lee Jordan had somehow lifted from the office of the school janitor, Mr. Filch. In short (long?), Harry’s cock had swelled to nearly twice its original length and girth.

“Hermione, what the bloody hell happened?!”

“Harry, I’m SO sorry, it was an accident!” whimpered Hermione. “You see, the train bumped over something and caused my hand to shake, so my wand ended up pointing at —“ 

Ron cut her off with a pained look. “—Look, Hermione, don’t bother explaining, just hurry up and undo it.”

Panicked, Harry shielded his straining member as best as he could. “Hold on a minute! I deserve to know exactly what you plan to do with that wand! What did you even do to me in the first place?”

“It was a Growth Spell,” explained Hermione, still not looking directly at Harry. 

“And how do you plan to “undo" it?” gritted Harry, who was beginning to feel a bit lightheaded from all the blood rushing to his lower region.

“A Shrinking Spell..?” said Hermione slowly. Ron coughed, tapping Hermione’s hand, and Hermione guiltily passed him his pea-sized duffel.

“Like hell I’m going to let you shrink me there, Hermione!” Harry glared furiously.

Hermione, flustered, yelled back. “Well what do you want to do? Wait and go to Madam Pomfrey?” Harry pondered the humiliating implications: disembarking the Hogwarts Express with a massive hard-on, risking being seen by his classmates, having to explain to Madam Pomfrey what had happened… possibly even show her the evidence— 

Harry decided against it. “Fine, but let’s discuss this. What can you pull up about the Shrinking Spell in your text?”

Hermione, relieved to have something else to look at, began rummaging through her miniature textbooks.

All three heads snapped to the door at voices coming down the hallway. Ron stood abruptly, face still a ruddy red. “I’ll..er.. just go stand watch in the hallway. Maybe someone will know a good Forgetfulness Charm, or perhaps I can just Scourgify my brain.”

——

Alone in the compartment, Harry and Hermione sat in pained silence as Hermione flipped through the pages. While he waited, Harry contemplated the size of his cock. _Would masturbating feel any different?_ He was dying to take it in his hands and give it a few good tugs.

“Aha! Engorgio and Reducio, here they are,” Hermione tapped the page eagerly. “Okay. Household items, plants, animals, humans…” she paused, and her face fell. “Oh.”

Harry felt his heart squeeze painfully in his chest. “Oh? What is ‘oh’? What does ‘oh’ mean, Hermione?”

Hermione’s cheeks burned as her eyes lifted from the page and met Harry’s. “The Engorgio Charm causes swelling and hardening of cells… so if you use the Reducio charm there’s a risk of damaging the cellular structure of the…area.”

“So, what do we do?”

“The book says that the fluids have to recede on their own before it’s safe to use the Reducio charm.” 

Harry groaned. “So what, I’m stuck like this?” 

“Well… not exactly,” Hermione admitted quietly. “There’s another way to get the swelling to go down.” 

Harry stared expectantly. Cheeks flaming, Hermione haltingly read the book’s explanation. “The affected area should be massaged manually until the swelling subsides on its own and the area is ready to be Reduced.” Her eyes met Harry’s, and she whispered the last part. “The book says it needs to be done by the caster of the charm."

At that, Harry groaned again, though this time it was for an altogether different reason.

  
Author's Note: Gosh, it's been such a long time since I've posted anything! For anyone who has read my Hunter x Hunter fanfics, I'm very sorry for the hiatus. I decided to jump back in to writing with a bit of smut from another fandom. :) I don't own any of the characters -that would be the lovely JK Rowling - I just took 'em out to play for a bit. Note: this is chapter 1 of a multi-chapter story.. I uploaded without noting that so it appears it is complete when it is not-- there is more to come!


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